Reducing the power loss in electric loads has been a focus of much development for some time. While early work focused on power transmission losses, more recent developments have also addressed power losses in 220 volt and 110 volt residential and commercial site load networks. Power efficiency meters connected between a utility metering device and a residential or commercial load have measured the power loss or efficiency of such a site load network.
It has been found that power loss can be reduced by altering the sinusoidal shape of the 60 cycle voltage supplied by a utility company. The object of such previous work was to reduce the transition time of the voltage from half peak value to half peak value. This was done with 110 volt or 220 volt power supplies connected between a utility metering device and an electric load.
An energy savings device, power supply having an internal dc battery, is disclosed in U.S. Pat. 3,319,074. The patent describes an external ac source which is rectified and applied to a load under control of a transistor. The dc battery compensates for fluctuations of the ac power source and is maintained in a fully charged condition. The problem with operation of the energy savings device is that, while the power supply is designed to maintain a constant voltage on the load, the power supply introduces additional power losses and does not cope with the varying demands of ac loads, insofar as efficient supply of energy is concerned.
U.S. Pat. 4,206,367 (Petruska, et al.) shows a 220 volt power supply having an internal dc battery and a charge/discharge circuit. The energy savings device operates to reduce the power drawn from the utility company supplied external ac source while servicing the residential load. The device is constructed to provide a continuous sinusoidal wave through opposite phase, coupled dc batteries but, due to the inherent delays in the batteries, can only achieve an approximated sinusoidal waveform which is not sufficient to power electric motors and power supplies of modern equipment used in residences and businesses.
Use of the power supply shown in U.S. Pat. 4,206,367, in cooperation with electrical loads, has resulted in the increased use of power consumption metering of the power supplied by public utilities to their customers. However, these power use meters presently are unable to accurately measure energy savings actually being attained.
One method of improving the actual, real time measurement of power consumption of the Petruska, et al. patent is the error compensating circuit described in U.S. Pat. No. 5,319,300 [Wood]. In the Wood patent, the error compensation or correction circuit includes a pair of capacitors straddling another capacitor or a rechargeable battery source and uses switching transistors to apply an instantaneous voltage level corresponding to the sinusoidal ac supply voltage by controlling the charging and discharging of the voltage storage elements (i.e. the capacitors and battery) which results in an applied reverse current flow to the power metering device furnished by the power company. The applied reverse current flow corrects the power consumption measurement of the metering devices attached across the electrical load.
A residential use or power consumption meter is connected directly to the utility power metering device and uses the 220 volt power supplied at that point to calculate and record (by magnetic rotating dial and hand pointers) the power consumption of the customer. Residential use, while sometimes at 220 volts; e.g. electric ranges and clothes dryers, is primarily delivered at 110 volts. This is accomplished by splitting the three-wire 220 volt supply line into two, two-wire 110 volt subcircuits in the residential distribution box; i.e., the circuit breaker box.
The energy savings device of the Petruska, et al. patent is a 220 volt device which is intended to be connected between the utility power metering device and the residential circuit breaker box. A power consumption meter is a 220 volt device which is intended to be connected between the utility power metering device and the energy savings device of the Petruska, et al. patent. Due to the fact that most (if not all) power consumption meters measure 220 volt current usage across the load to calculate residential power consumption at both 220 volts and 110 volts, an error in calculating the true power consumption can occur.
The ability of the energy savings device in the Petruska, et al. patent to react to changes in current demand was severely limited by the voltage storage devices (i.e. the batteries) which were a part of the error measurement and compensation circuit. The Wood patent makes significant strides forward in the elimination of voltage storage devices with very slow response times by substituting for these devices voltage storage elements with faster response times (i.e. the capacitors of the Wood circuit arrangement) which achieve a significant reduction in response time resulting in a more accurate error compensation for the instantaneous current draw. However, due to the continued use of the complex circuitry arrangement which included, for example, complimentary and opposing current flow compensation circuits, the instantaneous result was not the pure sinusoidal waveform which was desired.
An object of the present invention is to provide an electrical power energy savings circuit means for a 220 volt ac power delivery system having a substantially instantaneous response for delivering a nominal sinusoidal waveform.
A further object of the present invention is to incorporate such an improved energy savings circuit means into a residential power supply of the type shown in connection with the error compensation circuit of U.S. Pat. 5,319,300.
An additional object of the present invention is to provide a residential power supply with an electrical power energy savings circuit which reduces the 220 volts drawn from the utility company ac voltage supply during 110 volt load usage in a substantially instantaneous manner.
Other objects will appear hereinafter.